Gravity Probe B Experiment
Space is much like a flexible fabric containing massive bodies like sun, Earth and other planets, moons and all other objects. These massive objects "Bend" or "Drag" space. This was an unverified prediction of General Relativity until a satellite with four ultra smooth gyroscopes mounted on, was sent to orbit Earth to measure the bending of space-time.
Usually a gyroscope's axis points in a fixed direction AND IF EARTH IS REALLY DRAGGING SPACE, ITS AXIS SHOULD ALSO BE DRAGGED ALONG WITH IT. After precise measurements, the gyroscopes deviated 0.0018 degrees/year with reference to the guide star. This experiment proved Einstein's predictions right.
